Web sites, emails, and other electronic communications are fraught with fraud and deception. Users are commonly taken in by emails or web sites that seem to originate from trusted sources, but actually do not.
Current approaches to indicating trustworthiness of a site are either highly intrusive (such as requiring users to respond to dialogs), or restrictive (such as refusing to allow users access to unknown or reported-untrustworthy sites), or ineffective (such as providing a visual indicator that is easily ignored by users).
Accordingly, it would be useful to have a way to indicate trustworthiness to a user in a manner that is not intrusive or restricted, but also is not easily ignored.